\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{graphicx}

\begin{document}
\section*{1}
\subsection*{1}
$$N=10$$
$$
\begin{array}{ccc}
    f & g & h \\
    8.88178e-15 & -1.11022e-15 & 1e-16 \\
    7.99361e-15 & -1.33227e-15 & 1.3392e-17 \\
    1.77636e-14 & 7.77156e-16 & 9.07444e-19 \\
    -8.88178e-16 & -2.88658e-15 & 1.52416e-20 \\
    -5.32907e-15 & -4.44089e-15 & 2.32306e-24 \\
    -8.88178e-15 & 8.99281e-15 & 2.32306e-24 \\
    7.10543e-15 & 3.66374e-15 & 1.52416e-20 \\
    3.55271e-15 & 3.33067e-16 & 9.07444e-19 \\
    2.30926e-14 & 4.44089e-16 & 1.3392e-17 \\
    5.32907e-15 & 8.88178e-16 & 1e-16 \\
\end{array}
$$
\subsection*{2}
We choose $N=1000$
\subsubsection*{Image}
\includegraphics[scale=0.5]{A.png}
\subsection*{3}
The blue line is the result of function f.It's effect is the least.It has many violent towers because the processes in calculating $f(x)$ need many floats. 
The red line is the result of function g.It's better than f because the processes about floats reduce.
The green line is the result of function h.It's the best because the errors nearly don't accumulate.
\section*{2}
\subsection*{1}
$$UFL = 0.5, OFL = 3.5$$
\subsection*{2}
There are 25 numbers in FPN system.

0.5 -0.5 0.625 -0.625 0.75 -0.75 0.875 -0.875 1 -1 1.25 -1.25 1.5 -1.5 1.75 -1.75 2 -2 2.5 -2.5 3 -3 3.5 -3.5 0 
\subsection*{3}
\subsubsection*{Image}
\includegraphics[scale=0.5]{B1.png}
\subsection*{4}
There are 6 subnormal numbers in FPN system.

0.125 -0.125 0.25 -0.25 0.375 -0.375 
\subsection*{5}
\subsubsection*{Image}
\includegraphics[scale=0.5]{B2.png}
\end{document}
